Who is running a heat pump

[PurdueSD]

My shop is in progress 30x56
--30x36x10 and 30x20x12--
Total cubic feet=18000

It will have no windows, 2 8x10 insulated doors, 1 7x9 insulated and (1) 10x10 insulated.

6" fiberglass batts in the walls, and 9" blown in the ceiling

I live in Southwestern Indiana. Based on the information i have read a heat pump would be the most cost effective way to heat the garage in the long run. I do not have access to natural gas. I would like to keep the shop around 45-50 from Nov-Feb. Possibly bumpping the temp up on the weekends to 60ish.

Does anyone have the knowlege to size my needs (ton requirements)?
How much does a middle of the road X-ton heat pump run?
How many AMPs would this require to operate?
What type of cost to opperate would i be looking at?

Thanks for the help in advance!

 

[PurdueSD]

ohh....My cost per kWh is .078

 

[rickairmedic]

Purdue you are looking at a 3 & 1/2 to 4 ton to heat and cool your space . Most air handlers of that size are gonna need at least 2 30 amp breakers plus another 30 for the heatpump itself as far as pricing where in indiana are you I'm in louisville and carry Carrier equipment which if your close enough I could get for you at cost . There are many variables as far as cost goes . I sell alot of Hybrid heat ( dual fuel ) systems here which if you have propane is a way to go but with the temps you are wanting to keep a standard heat pump system would do the job .


Rick

 

[mike944]

Do you know what the underground temperature is in your area? It's 50-55 in many areas of the U.S.

If you only want to keep it at 45-50, forget the heat pump, why not just bury a coil of tubing and use a small circulating pump, and a heating coil with a blower fan. Theoretically, that should be able to maintain the garage at close to whatever the underground temperature is, and it should use much less energy than a heat pump. The only disadvantage to this system is, you couldn't "crank up" the the heat when you wanted to work in there, you'd need an auxillary source of heat to get it above underground temperature.

You'd need to bury a coil of tubing with a ground-source heat pump anyway, which is the most energy efficient kind of heat pump.


I've wanted to try this idea for a while now, as a way to keep unheated areas from freezing, but i live in a condo, and # 1 - I don'e have any unheated areas to try it out on, and #2 - i don't think the association would like me digging up the yard to install tubing!

 

[PurdueSD]

Do you know what the underground temperature is in your area? It's 50-55 in many areas of the U.S.

If you only want to keep it at 45-50, forget the heat pump, why not just bury a coil of tubing and use a small circulating pump, and a heating coil with a blower fan. Theoretically, that should be able to maintain the garage at close to whatever the underground temperature is, and it should use much less energy than a heat pump. The only disadvantage to this system is, you couldn't "crank up" the the heat when you wanted to work in there, you'd need an auxillary source of heat to get it above underground temperature.

You'd need to bury a coil of tubing with a ground-source heat pump anyway, which is the most energy efficient kind of heat pump.


I've wanted to try this idea for a while now, as a way to keep unheated areas from freezing, but i live in a condo, and # 1 - I don'e have any unheated areas to try it out on, and #2 - i don't think the association would like me digging up the yard to install tubing!

Hmmm, i never thought of geothermal. I always figured the cost would be very prohibative. Does anyone have anymore information or know of a website that can help me learn some of the details? Does anyone sell geothermal heat pumps as a system or is it a peice your own together type deal?

 

[PurdueSD]

Purdue you are looking at a 3 & 1/2 to 4 ton to heat and cool your space . Most air handlers of that size are gonna need at least 2 30 amp breakers plus another 30 for the heatpump itself as far as pricing where in indiana are you I'm in louisville and carry Carrier equipment which if your close enough I could get for you at cost . There are many variables as far as cost goes . I sell alot of Hybrid heat ( dual fuel ) systems here which if you have propane is a way to go but with the temps you are wanting to keep a standard heat pump system would do the job .


Rick

Great that would mean my planned 100Amp sub panel from the house's 200A service wouldn't be near enough power. So this would require a seperate service...ouch...that may change things.

 

[gesoffen]

Hmmm, i never thought of geothermal. I always figured the cost would be very prohibative. Does anyone have anymore information or know of a website that can help me learn some of the details? Does anyone sell geothermal heat pumps as a system or is it a peice your own together type deal?

When replacing my home heat pump, I did some serious investigation into Geothermal heat. I found it the right source for me except that I'm in the wrong area to have it installed. More specifically, I'm in the wrong area to have the vertical well drilled for the heat transfer. Drilling costs were $10k+ not including the actual heat pump. And that would not have included any repairs of likely damage to my driveway and yard by the heavy drilling equipment, tree removal to get the equipment to the drill spots, etc.. There are outfits that have made drill rigs much more compact (using a skidsteer as a drill rig) but non existed in my area. All in, I would have been around $20k + damage repair and tree costs. I ended up buying an air/air heat pump system for $4.5k.

Don't let the above discourage you. I found that for nearly all applications, the ground source heat pumps are by far the most efficient source of heating/cooling. In addition to lower cost per kWh or BTU equivalent of heat, you should have lower maintenance/replacement costs because the units are all indoors (no outside compressor), no burners or other associated dangers from combustion. It really depends on your local support of Geothermal. Its new enough that most mechanical contractors haven't seen it so your forced into a specialist. However, its gaining popularity though. With more competition comes lower cost. Maybe on my next heat pump replacement, they're be more drillers or better equipment thats friendlier to suburban lots.

IF you do a google search of Geothermal heat pump, you'll get a lot of hits. One of the companies that got me started with info was Water Furnace. Of course they're out to sell you a geotherm heat pump, but they do supply/link a lot of informative information.

 

[mike944]

Not all geothermal heat pumps require wells. The alternate is trenches in the yard, dug below the frost line, filled with tubing. But....you need a LOT of tubing, and therefore a lot of yard area to trench. gesoffen - your yard must not have been appropriate to doing this, or you were steered wrong by a contractor. Vertical wells for geothermal are often only dug in extreme circumstances.


Actually, i was suggesting possibly using just the coils (or wells) and no heat pump, just a water-circulating pump. Since he doesn't really need to heat above the temperature of the ground, you shouldn't need the heat pump portion. The only reason for the heat pump, is because the underground temperature of 55F is not usually warm enough to be usefull for much.

If that doesn't work, geothermal heat pumps are definitely the way to go for operating cost, but it depends on your objective. short-term cost, vs long-term cost. If you're planning to own that place for a long time, then operating cost is your concern. if you plan to be there short-term, you'll never pay-back the much higher installation cost of a heat pump.

 

[PAToyota]

There are outfits that have made drill rigs much more compact (using a skidsteer as a drill rig) but non existed in my area.

I recently saw a drill rig that could be towed by a fullsize pickup. Once set up, it could drill one well straight down and then angle the mast and pivot such that up to six more holes could be drilled out away from the initial hole. They were using it to run geothermal heat for houses in town on 1/8 acre lots. Pretty nifty setup!

As for the trenching and coils, excavation costs add up as well. Not quite as quickly as well drilling I'll grant you. But you're pretty much talking "out in the country" for those systems due to the area you need.

 

[HoosierBuddy]

I think a heat pump might be the best way for you to go. You'll have to sort of "play with" the idea of turning the temperature up and down as you need heat. While this works great with a big gas furnace, your heat pump may need to kick over to the backup resistance heating elements if you try to make it do too much too fast which drops your COP from say 3.0 to 1.0. It might work better to keep an even temperature through the entire season. Heat pumps are "right sized" for maintaining your temperature.

I like the concept of the hybrid system in that it replaces the resistive heating elements with a gas furnace, however in a garage situation you may not really be able to justify it. I guess you could consider swaping in a propane water heater in your house at the same time. That would save you money, get you more hot water and create an additional propane load to make it economical for you to maintain a propane supply on sight.

Just a thought.

Regarding the home grown geothermal idea? Dehumidification would be problamatic.

Phil

 

[russlaferrera]

I have a 3500 sq ft home heated with a "Water furnace" geothermal heating system. In 1996 the cost was $9300. My heating/cooling bills are between $150-230 (because of winter/summer rate changes).

I have 3 wells connected to each other, (about 300ft) The cost savings from my older heat pump is less than $ 5. per year.

I love the way it works as there is no outside unit to make any noise. The unit heats and cools (as all HP do). Dislikes are heat pumps have a slow heat/cool recovery rate .

I would consider all electric as it is 100% efficient or propane. Look of the cost og the heating unit , cost of fuel to make BTU, and life expend.

 

[RPH]

http://geoheat.oit.edu/pdf/pdfindex.htm

Check this site for papers on geothermal information.

 

[Blown71X]

I`ll weigh in on this a bit, and for the record i`m just north of indy.
My shop is 1920 SqFt with R19 walls under 1/2 plywood and R30 ceiling and I did an air to air heat pump, 14 seer 4 ton
The primary reason is I get (or did at that point More on that in a bit) a break on rates for being totally electric and to be honest the cost per season on my house (3 1/2 ton AtoA) was good enough that I felt it would be good to go that route in the shop, Well one thing that I really didn`t put much thought in was the overall volume and recovery time due to parking in there in the winter, this came to haunt me last february, as anybody in Indiana knows it was freeking cold the entire month, single digits alot of the time and Air to Air just flat can`t pull enough heat out of ambiants much lower that 20-25 degrees to do any good.
I have a logging thermostat and it spent much of the month in electric backup (30KW worth) Trust me you don`t want to stand anywhere near the electric meter when this is happening, if the disc came loose you would be killed I went to great pains this summer to make damn good and sure that everything was as airtight as is possible and am going to run it one more winter to see what happens, If things don`t work out I am going to convert to dual fuel of some sort Our wonderful utility no longer gives rate breaks to secondary service based off the primary so a seconday source of heating is no concern, $400+ electric bills just won`t cut it.

I checked into geo originally when this project started and it just wasn`t within the budget, No room for trenching due to trees and finger system for the house and well drilling was completely prohibitive (about 15k)

One other thing you need to consider is if you intend to keep your area at a constant temp (I do) as Bumping a heat pump up and down will cause the backup to come on, if this is electric you won`t be happy at the end of the month.

Due to a series of events that i`d rather not talk about I lost all my monthly expense data on both units this year, so at this point all I have is monthly averages with the A/C and it is from what I remember slightly lower than last year ($68) so hopefully this winter will be better.

Rick

 

[gesoffen]

gesoffen - your yard must not have been appropriate to doing this, or you were steered wrong by a contractor. Vertical wells for geothermal are often only dug in extreme circumstances.

1/5 acre wooded lot - not very friendly to horizontal trenching. The lot size itself wasn't a problem but the trees and access to the lot would have made horizontal trenching near impossible.

During the process, I talked to a geotherm heatpump contractor that is based about 150 miles south of the DC area where I live. When I mentioned the drilling costs in the area, he commented that he could charge 1/2 the price and still make a killing! However, I've since found out that permitting process for drilling in our county is a bit of a bear - its not a $10k bear but its enough of one that their aren't many drilling companies in the area, especially ones that can handle these limited access jobs.

 

[gesoffen]

I have 3 wells connected to each other, (about 300ft) The cost savings from my older heat pump is less than $ 5. per year.

I love the way it works as there is no outside unit to make any noise. The unit heats and cools (as all HP do). Dislikes are heat pumps have a slow heat/cool recovery rate .

Not take this thread to far OT but are you saying the operating cost difference from A to A heat pump versus an A to G heat pump are zilch!? If so, I'm surprised every other case I've read indicated a 2 to 1 cost difference or better favoring the AtoG. Granted, most of this info was dug up in my search for Geotherm info and since this technology is not mainstream in the consumer market, its tough to find info anywhere (except the Geotherm companies of course).

If the operating cost differences are next to nothing, then that blows the whole efficiency benefit out the window. However, not having an unsightly, noisy and exposed out door heat exchanger/compressor is a big benefit - not worth it to most for the added cost of Geotherm.

 

[trovato]

I have a logging thermostat and it spent much of the month in electric backup
Rick

OK, well I'm not going to let you get away with making a statement like that without explaining further! Do tell. What kind of logging thermostat are you using? Please tell us about what you're doing.

 

[rickairmedic]

Gesoffen the biggest problem with geothermal and what makes the cost differance so small is the initial cost to install with alot of folks having to drill wells it makes the initial outlay far more expensive than a standard air to air set up . I can get 20 seer or better out of air to air for around 10 grand most will spend twice that on air to ground and get maybe 25 seer so if you factor your initial cost into the equasion your not saving much going air to ground . I am sure as geothermal becomes more popular the costs will become less on them which will make them a better choice but currently at least in my area the costs outway the benifits.


Rick

 

[trovato]

rickairmedic,

I think a big factor here is where you are located. In a much colder place, it is much harder for an air to air heat pump to work. When the outside temperature drops too much, you end up on "backup", which in my case is resistive electric. If I got the exact same SEER out of a ground source system, but I never had to go to backup, I bet I would save a bunch.

 

[gesoffen]

rickairmedic,

That is the exact reason that I choose to stick with air to air for now. $20k+ for air to ground (including drilling costs) or $4.5k for air to air - easy choice.

What I was really interested in were real world operating costs (i.e. monthly kWh usage or electric bill) especially if someone made a recent conversion where one could compare the back to back differences.

 

[PurdueSD]

So limiting the options down to:

1. forced air propane furnace (would require a 250ish gallon tank)
2. Air to Air electric heat pump (Would require another 200 Amp service)

What would you choose?

I dont mind spending up to 5-6K for heat, but i do mind breaking the bank on utilities for the colder months. I also do have a friend that could get me the equipment at cost and would most likely help me install it at a minimum $.

How painfull would getting the power company to run me more power or a seperate feed be? The garage is approx 150' from the road and the house is approc 100 ft beyond that. I already have 450' of #4 wire and a number 8 ground, that i planned on using to steal 100A from the house, however a heatpump will kill this idea.

Honestly propane is sounding more and more like the most economical/ more friendly approach. In the long run, i may pay a little bit more for gas, but it seems like it would take an aweful long time to re-coupe the initial investment of heat pump.

 

[rickairmedic]

Purdue with your current limitations and depending on how far south you are in Indiana I would recomend hybrid heat ( dual fuel ) for your garage you will get the best of both worlds . The system can be set from a 55 degree outside air temp to a 35 degree outside air temp for changeover from heat pump to propane furnace . I set most of the ones I do at 35 degrees this will keep you from having to upgrade your electric service and also give you AC in the summer . I know here in the Louisville area most propane suppliers will provide a tank free of charge as long as you use their propane . The offer to get you equipment at cost still stands if you need it you can also feel free to PM me if need be .


Rick

 

[badgerboiler]

Your space is too small for questionable heat pump savings. Hydronic radiant floor heating. Put the tubing in the slab, under your feet and heat with a common gas-fired water heater.

MA